On my Berkshire, there is a compartment on the passenger side of the coach that has the water pump in it. There is a hose that area that is attached to the pump that you can put into the jug and when you turn on the pump, it will suck the anti freeze into the pump and pump it through the water lines. Just be aware that there are a couple of valves that need to be turned in order to suck the anti freeze out of the jug and not try to take water from the fresh water tank.
When you look at it you will see how this works.
Tom and Margaret
2014 Berkshire 390bh-60